1. Field of the Invention
The present invention relates to a channel switching apparatus for switching a flow direction of a fluid, and more particularly to an apparatus for switching a refrigerant channel of an air conditioner having both cooling and warming functions.
2. Description of the Prior Art
A refrigeration cycle in an air conditioner serves as a heating pump for a warming operation and a cooler for a cooling operation. Depending on a flow direction of a refrigerant, the air conditioner performs the cooling operation or the warming function by using a characteristic of the refrigeration cycle. Accordingly, the air conditioner having cooling and warming functions needs a refrigerant channel switching apparatus for switching the flow direction of the refrigerant and reversing the refrigeration cycle.
The refrigeration cycle of the air conditioner having cooling and warming functions is shown in FIG. 1. A compressor 1 compresses a refrigerant and discharges the compressed refrigerant into either an outdoor heat exchanger 2 or an indoor heat exchanger 4. A refrigerant channel switching device 5 is disposed between compressor 1 and heat exchanger 2 or 4 to switch the flow direction of the refrigerant from compressor 1 to either outdoor heat exchanger 2 or indoor heat exchanger 4 or from either outdoor heat exchanger 2 or indoor heat exchanger 4 to compressor 1. An expansion valve 3 is disposed between each output port of outdoor heat exchanger 2 and indoor heat exchanger 4 to connect the output ports and form a closed loop or a passageway of the refrigerant which is discharged from outdoor heat exchanger 2 or indoor heat exchanger 4 and a closed loop. A reference numeral 6 is an outdoor blower, and 7 is an indoor blower.
The refrigeration cycle initially performs the cooling operation, in which the refrigerant circulates in the direction of a solid arrow as shown in FIG. 1. Accordingly, the refrigerant discharged from compressor 1 circulates through refrigerant channel switching device 5, outdoor heat-exchanger 2, expansion valve 3, indoor heat-exchanger 4, refrigerant channel switching device 5, and compressor 1. Thus, the cooling operation is performed by indoor heat-exchanger 4 while outdoor heat-exchanger 2 serves as a condenser, and indoor heat-exchanger 4 serves as evaporator.
For the warming operation, the flow direction of the refrigerant is reversely shifted by the refrigerant channel switching device 5. Accordingly, the refrigerant circulates in the direction of a dotted arrow as shown on FIG. 1. The refrigerant discharged from the compressor 1 circulates through refrigerant channel switching device 5, indoor heat-exchanger 4, expansion valve 3, outdoor heat-exchanger 2, refrigerant channel switching device 5, and the compressor 1. Thus, the warming operation is performed in indoor heat-exchanger 4 while outdoor heat-exchanger 2 serves as an evaporator, and indoor heat-exchanger 4 serves as a condenser.
The refrigerant channel switching device used in the air conditioner having cooling and warming functions must switch the flow direction of the refrigerant without leakage of the refrigerant and include a precise switching mechanism for matching the input ports and output ports of the device. The conventional refrigerant channel switching device has the drawback of a complicated assembling process due to a complicated structure and a great number of parts. Particularly, due to their structural characteristics, it is very difficult to manufacture parts of the mechanism, assemble the complicated apparatus, and maintain the precise switching operation of the apparatus.
Furthermore, the conventional refrigerant channel switching device has a deteriorated reliability rate of its valve when used for a long period of time because the mechanism has to maintain a secure contact between the mechanism and the ports of the apparatus.